For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

Vehicle Care
California Proposition 65 WarningInstallation Procedure
Cut the quarter outer panel in corresponding locations to fit the
remaining original panel. The sectioning joint should be trimmed to
allow a gap of one-and-one-half-times the metal thickness at the sectioning
joint.
Create a 50 mm (2 in) backing plate from the unused portion
&nbs ...
Safety Locks
The rear door safety locks prevent passengers from opening the rear doors from
inside the vehicle.
Press to activate the safety locks.
The indicator light comes on when activated.
The rear door power windows are also disabled.
Press again to deactivate the safety
locks and power windows ...
Headlamp Mount Panel Replacement (MAG-Welding)
Note: According to different corrosion warranties, only the
regional mandatory joining methods are allowed.
Removal Procedure
Warning: Refer to Approved Equipment for Collision Repair Warning in the
Preface section.
Warning: Refer to Glass and Sheet Metal Handling Warning in the Preface sec ...